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机械毕业设计全套
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轴类零件的数控加工工艺设计与编程,机械毕业设计全套
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西安工业大学北方信息工程学院 毕业设计（论文）中期报告 题目： 轴类零件的数控加工工艺设计与编程 系 别 机电信息系 专 业 机械设计制造及其自动化 班 级 B090201 姓 名 杨 霞 学 号 40 导 师 张蔚宁 任京芹 2013年 3月 20日 nts1.设计（论文）进展状况 1.1在开题报告之前画了零件的二维和三维图如图 1和 2所示 : 零件二维 图 1 零件三维 图 2 1.2在开题报告之后所进展站工作 零件的结构工艺性是指所设计的零件在能满足使用要求的前提下制造的可行性和经济性，即所设计的零件结构应便于成形，并且成本低，效率高。 拟定零件的数控加工工艺规程，确定加工方案，选择合适的刀具，确定切削用量，确定零件的定位基准和装夹方式，对刀点和换刀点的选择，走刀路线的确定等。 1.2.1工艺分析 nts 本零件上由圆柱面、内孔、内圆锥面、圆弧面、沟槽、和螺纹等部分组成。零件车削加工成形轮廓的结构形状较复杂、需两头加工，零件的加工精度和表面质量要求都很高 该零件重要的径向加工部位有 003.038mm圆柱段（表面粗糙度 R=1.6m）、0 03.048 圆柱段（表面粗糙度 Ra=1.6m）、 R6mm圆弧与 R20mm圆弧相切过渡区、 o 03.023的内孔（表面粗糙度 Ra=1.6m）、长径比为 1:2的内锥（小端直径为 o03.023、 M20*2-6g三角形外螺纹，其余表面粗糙度均为 Ra=3.2m）。 零件符合数控加工尺寸标注要求，轮廓描述清楚完整，零件材料为 45钢，毛 坯 为 50mm*130mm 1.2.2 零件技术要求分析 小批量生产条件编程，不准用砂布和锉刀修饰平面，这是对平面高精度的要求，未注公差尺寸按 GB1804-M，热处理，调质处理， HRC25-35，未注粗糙度部分光洁度按 Ra6.3，毛 坯 尺寸 50mm*130mm。 1.2.3 加工方案 (1) 对图样上给定的几个精度要求较高的尺寸，编程时采用中间值。 (2) 在轮廓曲线上，有一处既过象限又改变进给方向的轮廓曲线，因此在加工时应进行机械间隙补偿，以保证轮廓曲线的准确性。 (3) 零图纸中含有圆柱度，为保证其形位公差，应尽量一次装夹完成左端面的加工以保证其数值。 (4) 本设计图纸中的各平面和外轮廓表面的粗糙度要求可采用粗加工 -精加工加工方案，并且在精加工的时候将进给量调小些，主轴转速提高。 (5) 螺纹加工时，为保证其精度，在精车时选择改程序的 方法，将螺纹的大径值减小 0.18-0.2mm，加工螺纹时利用螺纹千分尺或螺纹 环规 保证精度要求。 1.2.4 毛坯的分析 本零件的毛坯宜采用锻件，由棒料锯割，模锻毛坯至 40*425mm,使钢材经过锻压，获得均匀的纤维组织，提高其力学性能，同时也提高零件与毛坯的比重，减少材料消耗。 1.2.5 零件设备的选择 数控车床能对轴类或盘类等回转体零件自动地完成内外圆柱面、圆锥表面、圆弧面等工序的切削加工，并能进行切槽、钻、扩等的工作。根据零件的工艺要求，可以选择经济型数控 车床，一般采用步进电动机形式半闭环伺服系统。此类车床机构简单，价格相对较低，这类车床设置三爪自定心卡盘、普通尾座或数控液压尾座，适合车削较长的轴类零件。根据主轴的配置的要求选择卧式数控车床。数控车床具有加工精度高，能做直线和圆弧插补，数控车床刚性良好，制造和对刀精度高，能方便和精确地进行人工补偿和自动补偿，能够加工尺寸精度要求较高的零件。能加工轮廓形状特别nts复杂的表面和尺寸难于控制的回转体，而且能比较方便的车削锥面和内外圆柱面螺纹，能够保持加工精度，提高生产效率。所以对加工时非常有利的。 1.2.6 确定工件 的定位与夹具方案 （ 1）确定装夹方案 在数控车床上工件定位安装的基本原则与普通机床相同。工件的装夹方法影响工件的加工精度和效率，为了充分发挥数控机床的工作特点，在装夹工件时，应考虑以下几种因素： 1.尽可能采用通用夹具，必须时才设计制造专用夹具； 2.结构设计要满足精度要求； 3.易于定位和装夹； 4.易于切削的清理； 5.抵抗切削力由足够的刚度； 使用三爪自定心卡盘夹持零件的毛坯外圆，确定零件伸出合适的长度（应将机床的限位距离考虑进去）。零件需要加工两端，因此需要考虑两次装夹的 位置，考虑到左端的 38mm*35mm的台阶可以用来装夹，因此先加工左端，然后调头夹 38mm*35mm的台阶加工右端。 （ 2）定位 基准 工件的定位与基准应与设计基准保持一致，应防止过定位，对与箱体工件最好选择 “一面两销 ”作为定位基准，定位基准在数控机床上要仔细找正。 由于这个工件是个实心轴，末端要镗一个 30的锥孔，因轴的长度不是很长，所以采用工件的右端面和 48 的外圆作定位基准，使用普通三爪卡盘夹紧工件，取工件的右端面中心为工件坐标的原点，对刀点在（ 100.100）处。 由于此零件全部表面都需加工，应选用外圆及一端面为粗基准，然后通过 “互为基准的原则 ”进行加工。遵循 “基准重合 ”的原则。加工左端时选择在毛坯外圆柱段的右端外圆表面，加工右端时选择在 38mm外圆柱段的表面，以体现定位基准是轴的中心线。 1.2.7背吃刀量确定 背吃刀量根据机床，工件和刀具的 刚度来确定，在刚度允许的条件下，应尽可能使背吃刀量等于工件的加工余量，这样可以减少走刀次数，提高生产效率。为了保证加工表面质量，可留少量精加工余量，一般留 0.2-0.5mm。 总之，切削用量的具体数值应根据机床性能，相关的书册并结合实际经验用类比方法确定。总之，使主轴转速，切削深度及进给速度三者能相互适应，以形成最佳切削用量。 1.2.8 确定走刀顺序和路线 先粗后精 先主后次 nts 先面后孔 基面先行 此零件的的加工顺序如下： 预备加工 -车左端面 -钻中心孔 -镗孔 -内槽刀切内孔 -粗车左端外轮廓 -精车左端外轮廓 -调头 -车右端面 -粗车外轮廓 -精车外轮廓 -退刀槽 -粗车螺纹 -精车螺纹 工序 车左端面，将毛坯车为 127mm的棒料 工序 左端面打中心孔 选用 5mm的中心钻（手动钻孔） 工序 左端钻孔（钻 20mm深 32mm的孔）手动钻孔 工序 粗、精车左端内孔至要求尺寸 工序 粗、精车零件左端面各部、倒角 工序 调头车右端面将零件车至要求尺寸进 给路线 工序 调头粗、精车右端面各部倒角、切外螺纹退刀槽、三角形螺纹 1.2.9 工艺卡片和的 刀具选择 单位名称 产品名称或代号 零件名称 零件图号 轴 工序号 程序编号 夹具名称 使用设备 车间 001 三爪自定心卡盘 卧式数控车床 数控车间 工步号 工步内容 刀具号 刀具规格 主轴转速r/min 进给速度mm/r 背吃刀量 mm 备注 1 车端面 T01 35度车刀 350 0.1 0 手动 2 粗车外轮廓 T02 90度车刀 500 0.3 0.2 自动 3 精车外轮廓 T02 90度车刀 1000 0.1 0.1 自动 4 钻孔 尾座 20钻头 350 0.05 0 手动 5 粗镗孔 T03 镗刀 800 0.2 0.2 自动 6 精镗孔 T03 镗刀 900 0.1 0.1 自动 7 切槽 T04 切槽刀 350 0.05 0 自动 单位名称 产品名称或代号 零件名称 零件图号 轴 nts工序号 程序编号 夹具名称 使用设备 车间 002 三爪自定心卡盘 卧式数控车床 数控车间 工步号 工步内容 刀具号 刀具规格 主轴转速r/min 进给速度min/r 背吃刀量 mm 备注 1 车端面 T01 35度车刀 350 0.1 0 手动 2 粗车外轮廓 T02 90度车刀 500 0.3 0.2 自动 3 精车外轮廓 T02 90度车刀 1000 0.1 0.1 自动 4 切槽 T03 切槽刀 350 0.05 0 手动 5 粗车螺纹 T04 60 度螺纹刀 400 0.75 0.2 自动 6 精车螺纹 T04 60 度螺纹刀 600 0.75 0.1 自动 左端刀具卡片 产品名称或代号 零件名 称 典型轴 零件图号 序号 刀具号 刀具规格名称 数量 加工表面 备注 1 T01 硬质合金端面 35度车刀 1 粗、精车端面 2 T02 硬质合金 90度放型车刀 1 粗、精车外轮廓 左偏刀 3 T03 硬质合金镗刀 1 粗、精镗孔 4 T04 硬质合金内槽刀 1 切槽 5 尾座 硬质合金 20钻头 1 钻孔 右端刀具卡片 产品名称或代号 零件名 称 典型轴 零件图号 序号 刀具号 刀具规格名称 数量 加工表面 备注 nts1 T01 硬质合金端面 35度车刀 1 粗、精车端面 2 T02 硬 质合金 90度放型车刀 1 粗、精车外轮廓 左偏刀 3 T03 硬质合金车槽刀 1 切槽 4 T04 60度硬质合金外螺纹车刀 1 粗、精车螺纹 夹具图 3和 4所示： 夹具二维图 图 3 三爪卡盘 顶尖 夹具三维图 4 2.存在问题及解决措施 到目前为止，在毕业设计中遇到问题如下： 2.1 在零件的专用夹具设计时，觉得并没有真正理解专用夹具设计的用途，通过对相关资料的查阅，有了初步认识；最后确定用通用夹具三爪卡盘。 2.2 在后期对切削用量进行详细计算； 2.3 在对刀具选择和走刀路线的确定时，发现相关知识比较欠缺，将机械制造技术基础又一次学习加深理解； nts2.4 对数控加工工序卡片的制作不够完善； 2.5 对论文所涉及的知识认识得不够深刻，所以对命题的探讨不过深入。导致上述问题主要有两个原因，一是研究不够深入，二是撰写不够严密。针对这两个原因，解决方法有： （ 1） 对于论文所涉及的知识多理解及学习，多查阅相关书籍； （ 2） 对于写作过程中遇到的具体难题要多向指导老师请求援助； （ 3） 在设计遇到问题时多和同学交流，一起探讨，共同进步； （ 4） 自己也要对模具设 计方面的知识多了解，并深刻理解，在现有的基础上提高自己，完善自己，更好地完成设计任务。 3.后期工作安排 在此后期的任务，主要是： （ 1）完成零件的三维建模； （ 2）编制数控车削加工程序； （ 3）用 MasterCAM进行仿真； （ 4）完善前期工作； （ 5）编写设计说明书及校核图纸，交给导师查阅。 nts 指导教师签字： 年 月 日 nts17 2008.12 news mechanical English article Introduction of Machining Hoskins, Josiah Abstract: Machinery manufacturing industry on the world economy plays an important role, and the machining process is the establishment of machinery manufacturing technology and an important part of the critical work. In this paper, the output shaft is a fixture of the processing technology and design, focused on several important processing on the surface of a certain size, shape, location requirements, there are still some strength, surface roughness, andother requirements, but these will be reflected in the text . Key words: manufacturing; output shaft; processing technology; fixture. Have a shape as a processing method, all machining process for the production of the most commonly used and most important method.Machining process is a process generated shape, in this process, Drivers device on the workpiece material to be in the form of chip removal.Although in some occasions, the workpiece under no circumstances, theuse of mobile equipment to the processing, However, the majority of the machining is not only supporting the workpiece also supporting tools and equipment to complete. Machining know the process has two aspects. Small group of low-cost production. For casting, forging and machining pressure, every production of a specific shape of the workpiece, even a spare parts, almost have to spend the high cost of processing. Welding to rely onthe shape of the structure, to a large extent, depend on effective in the form of raw materials. In general, through the use of expensive equipment and without special processing conditions, can be almost any type of raw materials, mechanical processing to convert the raw materials processed into the arbitrary shape of the structure, as long as the external dimensions large enough, it is possible. Because of a production of spare parts, even when the parts and structure of the production batch sizes are suitable for the original casting, Forging or pressure processing to produce, but usually prefer machining. Strict precision and good surface finish, Machining the second purpose is the establishment of the high precision and surface finish possible on the basis of. Many parts, if any other means of production belonging to the large-scale production, Well Machining is a low-tolerance and can nts18 2008.12 news mechanical English article meet the requirements of small batch production. Besides, many parts on the production and processing of coarse process to improve its general shape of the surface. It is only necessary precision and choose only the surface machining. For instance, thread, in addition to mechanical processing, almost no other processing method for processing. Another example is the blacksmith pieces keyhole processing, as well as training to be conducted immediately after the mechanical completion of the processing. Primary Cutting Parameters Cutting the work piece and tool based on the basic relationship between the following four elements to fully describe : the tool geometry, cutting speed, feed rate, depth and penetration of a cutting tool. Cutting Tools must be of a suitable material to manufacture, it must be strong, tough, hard and wear-resistant. Tool geometry - to the tip plane and cutter angle characteristics - for each cutting process must be correct. Cutting speed is the cutting edge of work piece surface rate, it is inches per minute to show. In order to effectively processing, and cutting speed must adapt to the level of specific parts - with knives. Generally, the more hard work piece material, the lower the rate. Progressive Tool to speed is cut into the work piece speed. If the work piece or tool for rotating movement, feed rate per round over the number of inches to the measurement. When the work piece or tool for reciprocating movement and feed rate on each trip through the measurement of inches. Generally, in other conditions, feed rate and cutting speed is inversely proportional to。 Depth of penetration of a cutting tool - to inches dollars is the tool to the work piece distance. Rotary cutting it to the chip or equal to the width of the linear cutting chip thickness. Rough than finishing, deeper penetration of a cutting tool depth. Wears of Cutting Tool We already have been processed and the rattle of the countless cracks edge tool, we learn that tool wear are basically three forms : flank wear, the former flank wear and V-Notch wear. Flank wear occurred in both the main blade occurred vice blade. On the main blade, shoulderremoved because most metal chip mandate, which nts19 2008.12 news mechanical English article resulted in an increase cutting force and cutting temperature increase, If not allowed to check, That could lead to the work piece and the tool vibration and provide for efficient cutting conditions may no longer exist. Vice-bladed on, it is determined work piece dimensions and surface finish. Flank wear size of the possible failure of the product and surface finish are also inferior. In most actual cutting conditions, as the principal in the former first deputy flank before flank wear, wear arrival enough, Tool will be effective, the results are made unqualified parts. As Tool stress on the surface uneven, chip and flank before sliding contact zone between stress, in sliding contact the start of the largest, and in contact with the tail of zero, so abrasive wear in the region occurred. This is because the card cutting edge than the nearby settlements near the more serious wear, and bladed chip due to the vicinity of the former flank and lost contact wear lighter. This results from a certain distance from the cutting edge of the surface formed before the knife point Ma pit, which is usually considered before wear. Under normal circumstances, this is wear cross-sectional shape of an arc. In many instances and for the actual cutting conditions, the former flank wear compared to flank wear light, Therefore flank wear more generally as a tool failure of scale signs. But because many authors have said in the cutting speed of the increase, Maeto surface temperature than the knife surface temperatures have risen faster. But because any form of wear rate is essentially temperature changes by the significant impact. Therefore, the former usually wear in high-speed cutting happen. The main tool flank wear the tail is not processed with the work piece surface in contact, Therefore flank wear than wear along with the ends more visible, which is the most common. This is because the local effect, which is as rough on the surface has hardened layer, This effect is by cutting in front of the hardening of t he work piece. Not just cutting, and as oxidation skin, the blade local high temperature will also cause this effect. This partial wear normally referred to as pit sexual wear, but occasionally it is very serious. Despite the emergence of the pits on the Cutting Tool nature is not meaningful impact, but often pits gradually become darker If cutting continued the case, then there cutter fracture crisis. If any form of sexual allowed to wear, eventually wear rate increase obviously will be a tool to destroy failure destruction, that will no longer tool for nts20 2008.12 news mechanical English article cutting, cause the work piece scrapped, it is good, can cause serious damage machine. For various carbide cutting tools and for the various types of wear, in the event of a serious lapse, on the tool that has reached the end of the life cycle. But for various high-speed steel cutting tools and wear belonging to the non-uniformity of wear, has been found : When the wear and even to allow for a serious lapse, the most meaningful is that the tool can re-mill use, of course, In practice, cutting the time to use than the short time lapse. Several phenomena are one tool serious lapse began features : the most common is the sudden increase cutting force, appeared on the work piece burning ring patterns and an increase in noise. The Effect of Changes in Cutting Parameters on Cutting Temperatures In metal cutting operations heat is generated in the primary and secondary deformation zones and this results in a complex temperature distribution throughout the tool, workpiece and chip. A typical set of isotherms is shown in figure where it can be seen that, as could be expected, there is a very large temperature gradient throughout the width of the chip as the workpiece material is sheared in primary deformation and there is a further large temperature in the chip adjacent to the face as the chip is sheared in secondary deformation. This leads to a maximum cutting temperature a short distance up the face from the cutting edge and a small distance into the chip. Since virtually all the work done in metal cutting is converted into heat, it could be expected that factors which increase the power consumed per unit volume of metal removed will increase the cutting temperature. Thus an increase in the rake angle, all other parameters remaining constant, will reduce the power per unit volume of metal removed and cutting temperatures will reduce. When considering increase in undeformed chip thickness and cutting speed the situation is more comples. An increase in undeformed chip thickness and cutting speed the situation is more complex. An increase in undeformed chip thickness tends to be a scale effect where the amounts of heat which pass to the workpiece, the tool and chip remain in fixed proportions and the changes in cutting temperature tend to be small. Increase in cutting speed, however, reduce the amount of heat which passes into the workpiece and this increase the temperature rise of the chip in primary deformation. nts21 2008.12 news mechanical English article Further, the secondary deformation zone tends to be smaller and this has the effect of increasing the temperatures in this zone. Other changes in cutting parameters have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the power consumed per unit volume of metal removed and consequently have virtually no effect on the cutting temperatures. Since it has been shown that even small changes in cutting temperature have a significant effect on tool wear rate, it is appropriate to indicate how cutting temperatures can be assessed from cutting data. The most direct and accurate method for measuring temperatures in high-speed-steel cutting tools is that of Wright&Trent which also yields detailed information on temperature distributions in high-speed-steel tools which relates microstructural changes to thermal history. Trent has described measurements of cutting temperatures and temperature distributions for high-speed-steel tools when machining a wide range of workpiece materials. This technique has been further developed by using scanning electron microscopy to study fine-scale microstructural changes srising from over tempering of the tempered martensitic matrix of various high-speed-steels. This technique has also been used to study temperature distributions in both high-speed-steel single point turning tools and twist drills. Automatic Fixture Design Assembly equipment used in the traditional synchronous fixture put parts of the fixture mobile center, to ensure that components from transmission from the plane or equipment plate placed after removal has been scheduled for position. However, in certain applications, mobile mandatory parts of the center line, it may cause parts or equipment damage. When parts vulnerability and may lead to a small vibration abandoned, or when their location is by machine spindle or specific to die, Tolerance again or when the request is a sophisticated, it would rather let the fixture to adapt to the location of parts, and not the contrary. For these tasks, Elyria, Ohio, the company has developed Zaytran a general non-functional data synchronization West category FLEXIBILITY fixture. Fixture because of the interaction and synchronization devices is independent, The synchronous device can use sophisticated equipment to replace nts22 2008.12 news mechanical English article the slip without affecting the fixture force. Fixture specification range from 0.2 inches itinerary, 5 pounds clamping force of the six-inch trip, 400-inch clamping force. The characteristics of modern production is becoming smaller and smaller quantities and product specifications biggest changes. Therefore, in the final stages of production, assembly of production, quantity and product design changes appear to be particularly vulnerable. This situation is forcing many companies to make greater efforts to rationalize the extensive reform and the previously mentioned case of assembly automati on. Despite flexible fixture behind the rapid development of flexible transport and handling devices, such as backward in the development of industrial robots, it is still expected to increase the flexibility fixture. In fact the important fixture devices - the production of the devices to strengthen investment on the fixture so that more flexibility in economic support holders. According to their flexibility and fixture can be divided into : special fixture, the fixture combinations, the standard fixture, high flexible fixture. Flexible fixture on different parts of their high adaptability and the few low-cost replacement for the characteristic. Forms can transform the structure of the flexible fixture can be installed with the change of structure components (such as needle cheek plate, Multi-chip components and flake cheek plate), a non-standard work piece gripper or clamping elements (for example : commencement standard with a clamping fixture and mobile
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